Machines known at present for making stick ices can be considered as falling into two broad classes including rotary and linear machines, respectively.
Both of these known types of machines comprise a plurality of plates, each provided with a given number of molds and moving in a fixed path, and, arranged along this path, a measuring device for filling the molds, a brine-containing freezing tank, a stick-inserting device for introducing a stick in the semi-freezed product, and a device for removing a finished product from molds.
In the rotary-type machines, the plates with the molds are in the shape of a circular crown arc and are arranged close adjacent to each other so as to form, as a whole, a plane, endless circular crown which is advanced step by step.
This rotary type of machine has advantages, as compared with the linear type, in that there are no losses of product, since the traveling molds are at any time maintained in a same plane without overturning, and in that waiting time is minimized between thawing and subsequent filling and freezing steps, which steps are conducted at sufficiently short intervals of time to prevent any bacterial charges from developing in the molds as a result of the presence of product therein not removed by washing. The short waiting time between thawing and subsequent filling and freezing steps permits avoiding the need for washing the molds at the end of each cycle, thereby to save energy and to minimize brine consumption, in addition to avoiding loss of liquid product in the molds from thawing and withdrawing steps.
On the other hand, the rotary type machine has a number of disadvantages among which, in particular, the difficulties encountered in replacing the mold carrying plates since these plates are fitted to associated guides by means of metal joints sealingly screewed up through interventing silicone plastic packings or the like; the troublesome handling of same plates; as well as the fact that the different apparatus and devices mounted to this type of machine are difficult to install and/or to operate, the access to the central zone of the machine is extremely hard and, finally, in these rotary machines any product failing to be withdrawn from a mold must be removed by hand urgently.
This is a particularly troublesome difficulty.
It may, in fact, happen that an ice fails to be withdrawn from its mold, due, for example, to breaking of the ice-supporting stick or from other reasons; in this case, the operator has to empty the mold by hand but he has an extremely short time available for doing it. The mold carrying plates are, in fact, moved automatically so that a mold still containing a product could, at a next run, be again brought under the filling device. Thus, an operator is required to be permanently present to check good operation of the machine and to promptly intervene in order to prevent a further amount of product from being discharged onto an already filled mold and, therefore, from being spattered about: a very troublesome situation indeed.
In the machines of the second class, the linear types, the mold carrying plates are fastened to a driving chain running around a pair of toothed wheels, and are moved in a path comprising an upper straight portion with the measuring, freezing and withdrawing devices being arranged therealong, and a lower portion on which the plates are moved back in an overturned condition.
This solution has an advantage when compared with the rotary machine solution, in that any product not withdrawn from a mold will free itself of the mold --when this is moving on the lower portion of its path--as soon as thawing commences.
Moreover, in this type of machine, replacement of the molds, which are in the form of strips fastened to conveyor chains through bayonet joints, is facilitated, the same being true for the mounting of the various complementary apparatus.
However, some difficulties are connected to these latter machines owing to the long time interval between withdrawal of the finished product and subsequent filling of the molds, during which interval the mold plates run the lower portion of their path. This interval of time imposes, in fact, a washing of the molds in order to prevent formation of bacterial charges on that portion of product still adhering to mold walls. As a result, water and brine consumptions are higher and there is a loss in product, since that product remaining in the mold after ice withdrawal is not recovered, as is the case, on the contrary, with the machines of the circular type.